EPE Association: EPE 2017 - LS4a: Fault Coordination and Protection of DC Grids

EPE 2017 - LS4a: Fault Coordination and Protection of DC Grids
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2017 ECCE Europe - Conference > EPE 2017 - Topic 06: Grids and Smart Grids > EPE 2017 - LS4a: Fault Coordination and Protection of DC Grids

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   A Passive Hybrid HVDC Circuit Breaker Based on Thyristors
By Wenjie PAN [View]
[Download]

Abstract: This paper proposes a novel passive hybrid high-voltage DC circuit breaker based on thyristors. A current commutation circuit to turn off the thyristors is designed with elements of relatively low current and voltage ratings. Moreover, voltage balancing strategy is applied to protect the series-connected device.

   Advanced Negative Sequence Droop Control for Fault-Ride-Through Operation and System Support in Weak Grids
By Hendrik JUST [View]
[Download]

Abstract: A control concept is presented to include grid supporting schemes into the droop control of grid-supporting and grid-forming power electronic converters. This control scheme adopts advanced power reference strategies used for grid-feeding converters to voltage controlling converters during unbalanced faults. The strategies are evaluated first with respect to the maximum power injection in case of a fault, which is necessary for frequency and voltage support in the grid. Second, the impact on critical power converter quantities like power oscillations or current and voltage limits are discussed. Relevant fault types are identified and the related three-phase voltage waveforms are extracted. Finally, the optimum injection strategy for two different fault types depending on the sag depth is derived.

   Fault Identification Algorithm for MMC Based Hybrid High Voltage DC Transmission System for Deep-Water Oil and Gas Processing
By Rajesh SAPKOTA [View]
[Download]

Abstract: This paper presents an algorithm for determining fault section on Modular Multilevel Converter (MMC) based hybrid High Voltage DC (HVDC) transmission system. The hybrid transmission system consists of an overhead line followed by a subsea cable for deep-water oil and gas processing.The algorithm is based upon independent analysis of post-fault characteristic signals at each terminal. These characteristic signals are fed to the relay at the local station thus eliminating the need for communication channels between HVDC converter stations resulting in rapid fault section identification. The developed algorithm analyses characteristic signals generated at the terminal during these faults and are implemented to determine the faulty section and the fault nature (permanent or temporary).

   Hybrid Circuit Breaker for HVDC Grids with Controllable Pulse Current Shape
By Andreas JEHLE [View]
[Download]

Abstract: In this paper, two new hCB concepts for DC-grids are presented, which use a pulse current to extinguish the arc in the mechanical switch after opening. Both concepts are capable to adjust the pulse current amplitude/waveform to the fault current amplitude and so generate a slow current slope di/dt directly before the zero current crossing without large passive components for a fast and reliable fault clearing. By improving the controllability of the hCB and with a new control concept the capacitor volume of the first concept could be reduced by 60\% and the inductor volume by 88\% compared to the existing solution. At the cost of more active components, the capacitor volume could be even more reduced by 98.4\% compared to the first concept (99.4\% compared to the existing solution).

EPE 2017 - LS4a: Fault Coordination and Protection of DC Grids
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2017 ECCE Europe - Conference > EPE 2017 - Topic 06: Grids and Smart Grids > EPE 2017 - LS4a: Fault Coordination and Protection of DC Grids
	[return to parent folder]

	A Passive Hybrid HVDC Circuit Breaker Based on Thyristors By Wenjie PAN	[View] [Download]
Abstract: This paper proposes a novel passive hybrid high-voltage DC circuit breaker based on thyristors. A current commutation circuit to turn off the thyristors is designed with elements of relatively low current and voltage ratings. Moreover, voltage balancing strategy is applied to protect the series-connected device.

	Advanced Negative Sequence Droop Control for Fault-Ride-Through Operation and System Support in Weak Grids By Hendrik JUST	[View] [Download]
Abstract: A control concept is presented to include grid supporting schemes into the droop control of grid-supporting and grid-forming power electronic converters. This control scheme adopts advanced power reference strategies used for grid-feeding converters to voltage controlling converters during unbalanced faults. The strategies are evaluated first with respect to the maximum power injection in case of a fault, which is necessary for frequency and voltage support in the grid. Second, the impact on critical power converter quantities like power oscillations or current and voltage limits are discussed. Relevant fault types are identified and the related three-phase voltage waveforms are extracted. Finally, the optimum injection strategy for two different fault types depending on the sag depth is derived.

	Fault Identification Algorithm for MMC Based Hybrid High Voltage DC Transmission System for Deep-Water Oil and Gas Processing By Rajesh SAPKOTA	[View] [Download]
Abstract: This paper presents an algorithm for determining fault section on Modular Multilevel Converter (MMC) based hybrid High Voltage DC (HVDC) transmission system. The hybrid transmission system consists of an overhead line followed by a subsea cable for deep-water oil and gas processing.The algorithm is based upon independent analysis of post-fault characteristic signals at each terminal. These characteristic signals are fed to the relay at the local station thus eliminating the need for communication channels between HVDC converter stations resulting in rapid fault section identification. The developed algorithm analyses characteristic signals generated at the terminal during these faults and are implemented to determine the faulty section and the fault nature (permanent or temporary).

	Hybrid Circuit Breaker for HVDC Grids with Controllable Pulse Current Shape By Andreas JEHLE	[View] [Download]
Abstract: In this paper, two new hCB concepts for DC-grids are presented, which use a pulse current to extinguish the arc in the mechanical switch after opening. Both concepts are capable to adjust the pulse current amplitude/waveform to the fault current amplitude and so generate a slow current slope di/dt directly before the zero current crossing without large passive components for a fast and reliable fault clearing. By improving the controllability of the hCB and with a new control concept the capacitor volume of the first concept could be reduced by 60\% and the inductor volume by 88\% compared to the existing solution. At the cost of more active components, the capacitor volume could be even more reduced by 98.4\% compared to the first concept (99.4\% compared to the existing solution).